Update free-programming-books-subjects.md

books/free-programming-books-subjects.md

@@ -21,7 +21,6 @@ Books that cover a specific programming language can be found in the [BY PROGRAM
 * [Data Science](#data-science)
 * [Database](#database)
 * [Docker](#docker)
-* [Database](#database)
 * [Game Development](#game-development)
 * [Graphical user interfaces](#graphical-user-interfaces)
 * [Graphics Programming](#graphics-programming)
@@ -260,18 +259,6 @@ Books that cover a specific programming language can be found in the [BY PROGRAM
 * [Uncomplicating Kubernetes](https://livro.descomplicandokubernetes.com.br/en/) - Jeferson Fernando
 
 
-### Database
-
-* [Database Design – 2nd Edition](https://opentextbc.ca/dbdesign01/) - Adrienne Watt, Nelson Eng @ BCcampus Open Pressbooks (HTML, PDF, EPUB, Kindle)
-* [Database Explorations](http://www.dcs.warwick.ac.uk/~hugh/TTM/Database-Explorations-revision-2.pdf) (PDF)
-* [Database Fundamentals](http://public.dhe.ibm.com/software/dw/db2/express-c/wiki/Database_fundamentals.pdf) (PDF)
-* [Databases, Types, and The Relational Model: The Third Manifesto](http://www.dcs.warwick.ac.uk/~hugh/TTM/DTATRM.pdf) (PDF)
-* [Foundations of Databases](http://webdam.inria.fr/Alice/)
-* [Readings in Database Systems, 5th Ed.](http://www.redbook.io)
-* [Temporal Database Management](http://people.cs.aau.dk/~csj/Thesis/) - Christian S. Jensen
-* [The Theory of Relational Databases](http://web.cecs.pdx.edu/~maier/TheoryBook/TRD.html)
-
-
 ### Data Science
 
 * [A Programmer's Guide to Data Mining](http://guidetodatamining.com) - Ron Zacharski (Draft)